I just thought of an etiquette disaster from Thanksgiving three years ago - I ought to submit it to the site but I'll just tell it here.
I have this sister in law who must be the center of attention at all times. If she's not feeling like the most important person in the room, she creates some kind of drama until she is. She is the mother of my nephew, who at the time (three years ago) was my parents only grandchild. SIL and family were scheduled to move to a military base cross-country just a few weeks after Thanksgiving and my brother was being deployed shortly to Iraq, so naturally my parents wanted to spend time with their only grandson and son before they all moved so far away.
My mom was hosting Thanksgiving, as usual. My mom is a diplomat's wife, so etiquette is very important to her. She's also the sweetest woman you could hope to meet. Well I have some close friends, a husband and wife who are living far away from their own families and were going to be alone on the holiday. My mom has met them several times before, and she suggested that we invite them over for Thanksgiving dinner. I thought that was a fine idea, I asked them several weeks in advance and they were delighted to accept. My parents house is about a 3 hour drive away, so we made arrangements to ride down together and spend the night. My SIL, brother and nephew would be there, along with various other family members.
Three days before Thanksgiving, my mom was talking to my SIL on the phone and mentioned that my friends (Jane and Jon) would be coming. My SIL THREW A FIT. She had decided that she does not like Jane and Jon because they wouldn't let my nephew touch their dog (their dog has been unpredictable around small children, and I was extremely grateful to them for taking the initiative to point this out and keep the dog away from my nephew rather than run the risk of him getting bitten). Anyway, my SIL thought they were rude for this and decided she didn't like them so on hearing that they were invited to dinner she just lost it. She said that she wouldn't come unless my mom UNINVITED this couple. My mom, close to tears at this point, said that she couldn't do that and pleaded with SIL to make a go of it, even if she wasn't all that fond of the couple. SIL would not budge. She then started making threats. Eventually, she swore that if my mom wanted to see her son and grandson at all before they left, that she would just have to call the couple and tell them that they were not welcome for Thanksgiving after all.
My poor mom. This woman is usually graceful and cool in the most awkward of positions, and yet she was crying when she called me to tell me this. I was livid. I wound up calling to explain the situation to my friends and "un-invite them" for the holiday, thereby throwing myself straight into e-hell. But I just couldn't risk my SIL not letting my parents see their grandson and soon-to-be-deployed son.
Isn't that awful? Please don't yell at me - I honestly still haven't gotten over my role in the situation.